Crystal structure and properties of Bi1 − x Ca x FeO3 and Bi1 − x Ca x FeO1 − x Ti x O3 solid solutions

Structural, Dielectric, Magnetic and Magneto-Dielectric Properties of (1-x)BiFeO3–(x)CaTiO3 Composites

“…Thus, we predict that for pure BFO (x=0), the crystal structure should be rhombohedral (space group R3c) while for x = 0.1 and x=0.2, it should be the monoclinic phase (space group Cc), and for x = 0.3 samples, the crystal structure should be orthorhombic (space group Pbnm). These observed structural changes in samples are consistent with an earlier report presented in Ref 27,28. It can be concluded that the concentration range can expand the structural stability of the polar rhombohedral phase by co-doping with Ca 2+ and Ti 4+ ions [28,29].…”

“…These observed structural changes in samples are consistent with an earlier report presented in Ref 27, 28. It can be concluded that the concentration range can expand the structural stability of the polar rhombohedral phase by co-doping with Ca 2+ and Ti 4+ ions [28,29]. The concentration phase transition from polar to non-polar orthorhombic phase is another essential difference of the Ca/Ti doping approach.…”

Multiferroic bismuth ferrite-based materials for multifunctional applications: Ceramic bulks, thin films and nanostructures

“…58 In addition, different phase boundaries were reported in other BFO-based ceramics with both sites being doped, 58,141,[163][164][165][166][167][168] such as R-T by La&Ti, 165 R-Pbnm by Ca&Nb, 166 R-pseudotetragonal by Ba&Ti, 141 and O by Pr&Ti. 168 On the other hand, it can also be seen from Table 3 that the phase structure of BFO remains almost unchanged when combinations of some elements are doped, [169][170][171][172][173][174][175][176][177][178][179][180][181][182][183][184] such as La & (Nb, 169 Zr, 170 Fe, 171 Mg 172 ), (Ho, 173 Ca, 174 Pr, 175 Gd 179 ) & Ti, Zn&Ni, 175 Ca & Mg, 176 Ho & Ni, 180 Y & Zr, 181 Ba & Ni, 183 and Sm & Co. 604 Poor ferroelectric and piezoelectric behavior were generally observed in spite of the enhancement in magnetic behavior. and tetragonal phases (0.95~1.0).…”

Electrical Properties of Ca-Doped BiFeO3 Ceramics: From p-Type Semiconduction to Oxide-Ion Conduction

“…Several studies into A-site substitution of isovalent (La 3+ , Nd 3+ , and Sm 3+ ) or acceptor (Ca 2+ , Sr 2+ , Ba 2+ , and Pb 2+ ) cations for Bi and B-site substitution of donors (V 5+ , Nb 5+ , Mn 4+ , or Ti 4+ ) for Fe have been carried out in order to improve the magnetic and ferroelectric properties. With A-site doping of Ca 2+ , the phase diagram of the resulting Bi 1– x Ca x FeO 3−δ solid solution contains several phase fields but disagreements over composition limits. − The most recent studies , show rhombohedral ( R 3 c ) and tetragonal, pseudocubic phase fields for 0 ≤ x < ∼0.07 and 0.2 ≤ x < 0.5, respectively, with a two-phase mixture for intermediate compositions.…”

“…It appears to be well-established − , that the oxidation state of Fe is Fe 3+ , and, consequently, charge compensation in Ca-doped BiFeO 3 is by oxygen vacancies. However, there is disagreement over the nature of the electrical properties.…”